Date: Wed, 7 Jan 2009 08:42:06 -0800 From: Joel Jacobson <jjacobson@panasas.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-geom@freebsd.org Subject: Re: performance problem with gstripe Message-ID: <F89B4A24-E877-47E1-89FD-94F1D91761CE@panasas.com> In-Reply-To: <gk19r9$p9m$1@ger.gmane.org> References: <4AD370A6-2226-442F-BD80-8CFD4045B094@panasas.com> <gk1664$g6d$2@ger.gmane.org> <CA9F4E99-5819-4FDB-B8F4-8AA21759942B@panasas.com> <gk19r9$p9m$1@ger.gmane.org>
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still works badly at 64k, but works well if i use 32k (and have kern.geom.stripe.fast=1). that being said, i was only seeing 64k I/O through ufs when i was doing the 256k stripe, so im still not sure why this matters. i have a somewhat hidden agenda here, too, in that i have my own filesystem that suffers the same problem im seeing with dd. i figured there was something ufs does which i do not, and was trying to figure out what that might be. it works fine on 4.6.2 using ccd and a 256k stripe size [and i send 128k I/O requests, which is what i would prefer to see sent to the driver, rather than 64k]. - j On Jan 6, 2009, at 8:08 PM, Ivan Voras wrote: > Joel Jacobson wrote: >> here's what i did: > >> ca-sbox-2# dd if=/dev/zero of=/dev/stripe/d0 bs=512k count=4096 >> 4096+0 records in >> 4096+0 records out >> 2147483648 bytes transferred in 34.124683 secs (62930508 bytes/sec) > >> ca-sbox-2# dd if=/dev/zero of=/mnt/bigfile bs=512k count=4096 && >> /usr/bin/time sync >> 4096+0 records in >> 4096+0 records out >> 2147483648 bytes transferred in 11.081184 secs (193795502 bytes/sec) > > > Hmm ok, you might be hitting the MAXPHYS problem. Could you try and > create your gstripe array with a stripe size of 64 kB and 32 kB and > test > on those ? >
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